99 Alero Check Engine Light and Idle problems

I just put a different 2.4 engine in my 99 alero. It drives well for the most part but my ETC OFF light is on my fog lights don't work and the check engine light is on. Also at about 20 to 40 MPH when you let off the Gas the engine pulsates from 1k to 1500 RPM, about three of four times. I hooked it up to a GM tech 2 scan tool and while it was hooked up everything worked again, but as soon as you unhook it after a minute or so the problems start right back up. Any ideas of what it could be?? I'm almost thinking it could be a grounding problem

The ETC light is on because the check engine light is on. Since the ETC relies on the engine being at 100% for it to work it shuts off as a default if it sees the check engine light regardless of the problem that turned the light on.

Did you check the PCM for codes?

It threw a P0507 Idle Air control Higher RPM than expected??

What was your TPS voltage?

I'm not sure i didn't write that down

Found out the problem the Intake wasn't on all the way... crap that makes me feel dumb ha ha